Liquid fuel burner



Jan. 18,1944. .L H. MclLvAlNE ETAL LIQUID FUEL BURNER Filed Juiy 5, 1941 2 Sheets-Sheet l LIQUID FUEL BURNER Filed July 5. 1941 2 Sheets-Sheet 2 Patented Jan. 18, 1944 LIQUID FUEL BUR-NER .l'olin H. Mcllvaine and Peter I. Hallman, Philadelphia, Pa., assignors to McIIvaine Burner Corporation, Chicago, Ill., a corporation of y Illinois Application July 5, 1941, Serial No. 401,128

12 Claims.

This invention relates to liquid fuel burners, commonly referred Ato as oil burners, suitable for industrial or domestic heating, and is particularly concerned with an improved fire pot or combustion head. In our Patents 2,193,829 and 2,208,851, we disclosed a combustion head of builtup sectional construction, in which a metallic overflow pan or base supports a metallic burner tray and an enclosing hood structure therefor, the hood in Patent 2,208,851 being made in one piece of refractory material. In our Patent 2,193,829 the burner tray was provided with an oil vaporization groove, and in our Patent 2,208,- 851 a transverse oil retaining Wall was provided near the front por-tion of this vaporization groove, reaching to flame pockets at the opposite ends of the groove, where wicks were provided behind the retaining wall to absorb oil and distribute the name as evenly as possible to the two pockets and also make reasonably certain that the flame on a low setting of the burner would stay close to the front portion of the groove and thereby prevent extinguishment of the llame while also keeping the groove portion of the tray hotter. While the construction of the later patent mentioned gave better performance than the construction -of the earlier patent, the wicks were found to be objectionable for certain reasons, one being that it was difficult to obtain a true balance between the flames from the two pockets due to the fact that the wicks would invariably not have quite the same absorption character-V istics, and even though they might perform fairly evenly at the outset they were apt to give unbalanced operation later. ject of our present invention to further improve the operation of the combustion head by eliminating the wicks and forming the bottom of the oil vaporization groove so as to provide ramps at a small angle to the horizontal plane of the tray, rising from a low level at the middle of the groove behind the oil retaining wall to an intermediate level at the llame pockets, and then rising from that intermediate level to a higher level at the middle of the vaporization groove in front of the oil retaining wall, whereby better to make certain of distributing the flame equally to the two pockets and at the same time make certain that the flame on a 10W setting 0f the burner will stay close to the front portion of the groove and thereby prevent eXtinguishmen-t of the flameand also keep the groove hotter.

Another object is to provide a secondary air inlet for the combustion head for the admission of air from the air conduit directly beneath the It is the principal ob- I' tray at a point remote from thev bottom of the oil vaporization groove, whereby tokeep the overiiow pan as cool as possible and keep the tray from over-heating, without interfering with good vaporization of the oil in the groove, the airdelivered under the tray being directed away from the grooved portion so as to flow across the bottom of the tray and up around` the ed-ges thereof and into the flame, where it serves further to support combustion.

The invention is hereinafter described by reference to the accompanying drawings, in which-` Figure 1 is a fragmentary viewv in side elevation of a combustion head or fire pot made in accordance with our invention;

Fig. 2 is a horizontal section, approximately on the line 2-2 of Fig. 1; v

Fig. 3 is a vertical section, approximately on the line 3-3 of Fig. 2, and l Figs. 4 and 5 are vertical cross-sections through the tray taken on the correspondingly numbered lines of Fig. 3, looking in the directions indicated by the arrows.

The same referencenumerals are applied to corresponding parts throughoutthe views.

The present invention being vconcerned pri. marily with the combustion head or fire pot, the rest of the oil burner has been omitted from the general view, Fig. l, andA atany rate the restof the burner is disclosed in the two patents previously mentioned, so` that it will suffice to state that the air tube or conduit 6, for delivering `air to the combustion head 1, has airv supplied thereto under pressure. by a centrifugal fan in a blower housing communicating with the other endof the air conduit. The pipe. 8, indicated in Figs. 2 and 3, delivers oil to the combustion head and extends lengthwise inside the air conduit. It communicates at its other end with a control valve arranged to be adjusted to regulate the oil feed according tothe. heat demand, the oil flowing by gravity through the pipe 8 to the combustion head, where it is vaporized and the vapor is mixed with air and burned in the novel manner described in the aforesaid patents andalso briefly described hereinafter. The oil feed is regulated simultaneously with the. adjustment of an air shutter on the blower housing, as described in McIlvaine Patent 1,797,293, so that the correct amount of air will be supplied to the. combustion head in proportion to the oil sup'- plied, the oil and air being proportioned correctly as the .control valve is opened wider and Wider at each step in the progressive opening of the shutter plate, whereby to obtain good combustion in the low flame, which serves as a pilot, and in the various intermediate sized flames, as well as in the high flame. In the event the flame in the combustion head is accidentally extinguished, oil overflows the tray 9 into the overflow pan I and is drained through an outlet neck II onl thebottom of the pan I0 and conducted through a return pipe I2 to a trip bucket, forming part of an automatic shut-off mechanism, so as to discontinue oil flow to the ccmbustion head.

The combustion head consists of three parts:

(1) The metallic overflow pan I0 cast preferably integral with the end of the air conduit 6;

(2) The metallic burner tray-9 supported in the pan I Il, and

(3) The enclosing hood or cover I3 of ceramic material, notched as indicated at I 4 to fit over the end of the air conduit 6, and supported onl the pan I0 so as to surround the tray 9.

The pan I0 and hood I3 together constitute a casing wherein the tray 9 is enclosed and into which air from the conduit 6 is delivered for mixture with the vapors rising from the tray 9 so as to supply a flame, which on certain intermediate llames and on high llame projects upwardly through the'central top opening I4 in the hood. This sectional construction of the combustion head is of advantage, because it allows each part to expand and contract freely relative to the other parts, whereas a re pot cast in one piece would be apt to crack due to uneven heating. In that way we are enabled to use ordinary cast iron for the metal parts instead of special heat-resisting metals` thus eecting an appreciable saving in cost. 'Furthermore the sectional construction makes for simpler and less expensive individual castings and it permits making the hood I3, which is subjected to the most intense heat, of refractory or other heatresisting material. Sectional construction also enables replacement of any part separately in the event it cracks or burns out, and such replacement means very little expense as compared' to the necessity for replacing the entire head. The most expensive part of the assembly, namely, the combined overflow pan III and air conduit B, is safeguarded against likelihood of cracking, due to heating, by the fact that the thick tray 9 shields the overflow pan from the heat, the overllowpan being further protected against overheating by the circulation of air under pressure between the pan and tray as hereinafter described. The overflow pan I 0 has an upwardly projecting outer rim I5 and an upwardly projecting annular bead I6 in substantially concentric relation to the rim, and the hood I3 is supported on the pan between the rim and bead on a plurality of downwardly projecting feet I1 molded integral with the hood. The hood is suitably cemented inv place. as indicated at' I8. The bead I6 defines the rim of a drain cavity I9 in the center of4 the pan Ill, communieating with the outlet neck Il, as indicated at in Fig. 2. The cavity I9 has the same general shape as the burner tray 9, which appears in plan viewv in Fig. 2. The tray has feet 2I to support` the same in elevated relation to the bottom of the cavity I9. as clearly indicated in Fig.,3, to permit free flow of oil to the drain opening 20 and also permit air circulation under the tray, as will soon appear.

The tray 9 has'an inwardly and downwardly curved hood portion 22 cast integral therewith,

tion groove 23 provided in the bottom of the tray, the hood being spaced upwardly from the bottom of the groove to the extent shown in Fig. 3. The straight outer edge 24 of the hood has abutment with the end of the air conduit 6, along the top wall thereof, so as to locate the tray 9 squarely in relation to the end of the air conduit. A substantially vertical outer wall 25 on the tray next to the oil vaporization groove 23 and under the outer end portion of the hood 22 is disposed in transverse relation to the lower portion of the discharge end of the air conduit 6, as clearly appears in Figs. 2 and 3, and has a notch 26 thereinto receive and locate the downwardly bent discharge end of the oil pipe 8, so as to have oil discharged into the groove 23 approximately at the middle thereof. Now, obviously with the air entering the combustion head from the conduit 6 between the top of the wall 25 and the Ibottom o1 the hood 22, it follows that the incoming air will be deflected downwardly by the curved inner end portion of the hood toward the groove 23, and since the wall 25 forms a transverse baille with respect to the air current, a whirling motion of some of the air on substantially horizontal axes will be set up in a clockwise direction, as indicated by the arrows a in Fig. 3. These may be termed eddy currents. The groove 23 is of sufficient length in relation to the width of the discharge end of the air conduit, as indicated in Fig. 2, and there are, moreover, two obstructions or baffles 29 and 39 projecting upwardly from the wall 25 on opposite sides of the oil pipe locating notch 26, so that there are shielded llame pockets 3| and 32 provided in the opposite ends of the groove 23, protected from the direct force of the incoming air. This results in a whirling motion of air 'on vertical axes in the flame pockets 3I and 32, as indicated by the arrows b. Now, since the top of the wall 25 is appreciably below the bottom of the curved inner end portion of the hood 22, some air flows nearly straight through from the air conduit into the combustion head over the groove 23, as indicated by the large gently curved arrow c in Fig. 3. This air flowing nearly straight through carries with it the eddy currents a, and b, as represented in Fig. 2. The tray 9 which upon starting the burner has been preheated Iby a gas torch, or in some other suitable manner, and which thereafter remains heated .by the ames of the burning combustible mixture of oil vapors and air, is hot enough in the groove 23 to vaporize the raw oil upon Contact thereof with the groove. The oil vapors in the groove are picked up by the whirling air currents a and b in what may be termed premixing; and then these rich mixtures coming in contact with the main air current c form a leaner mixture that will burn with a clean hot llame. The flame is visible through the opening I 4 on low as two distinct tongues issuing from the vicinity of the pockets 3| and 32 onto the spirally formed bottom 33 of the tray, thus indicating how great an effect these pockets have upon the operation of the combustion head, because without these pockets, there would be danger of the ame being blown out. The baliles 29 and 39 shield the pockets from the direct force of the air current so that the flames originating therein will not be extinguished. The baflles 29 and 30 are closer together than the walls 34 and 35 defining the sides of the spiral Ibottom 33, thereby leaving the side portions of the spiral surface also somewhat protected from the direct force of the air discharged toward the middle of this surface.

When the burner is turned up to middle sized flames or to a high flame, there are no longer two distinct tongues of flame visible but only one large flame formed from these two flames, which as it builds up gradually reaches farther and farther over the spiral bottom 33 of the tray and iinally issues from the head through the central top opening M with a spinning motion, as indicated by the arrows d. in Fig. 2. The hood I3 confines the air delivered to the combustion head and causes it to mix into the flame to support combustion. The arne in the high setting of the burner is best described as an inverted cone having a counterolookwise spinning motion. This direction of motion results from the way the air is delivered into the combustion head at one side of the hood i3 between the vertical walls 311 and 35 of the tray. The wall 35 is substantially semi-circular and surrounds the spiral surface 33. The latter has a gradual rise from the groove 23 through approximately 180 and then, as indicated at Sli, has an abrupt rise to deilect the flame upwardly and out through the opening Id.

in accordance with the present invention, the

tray Si is provided with a substantially vertical oil f retaining wall 3'! in the groove 23 near 'the wall 25, so as to divide the groove a3 into a narrow trough 38 between the walls 25 and :3l and a wider trough B in front of the wall 3l. The bottom of the narrow trough 53 is defined by ramps dii and fil which are upwardly and outwardly inclined from a midpoint in the trough, indicate-d by the dotted line t2, at a small angle to the horizontal plane of the tray toward the substantially horizontal bottoms i3 and ifi of the flame pockets 3l and 32, respectively. The bottom of the wider trough 39 is defined by ramps d and t@ which are upwardly and inwardly inclined at substantially the same small angle to the horizontal plane of the tray as the ramps #lil and il from the substantially 'horizontal bottoms 43 and le of the flame pockets toward the midpoint of the trough 35i, indicated by the line lill. There is an inwardly projecting substantially vertical boss El formed on the inner side of the wall 25 at the midpoint of the trough 3S, and a vertically extending groove 2li is provided in the front side of this boss directly beneath the discharge end of the oil pipe 8, so that in the event the discharge end of the pipe does not happen to be located accurately over the midpoint of the trough 38, the groove 2E will direct the stream of oil toward the midpoint. The trough 33 is primarily a means for delivering the oil to the iiame pockets tl and 3?. so that the flames from these pockets are as near equal size as possible. Very little vaporzation takes place in the trough 3d. The wall ill defining the outer side of the trough terminates at the upper ends of the ramps il and il and next to the flame pockets 3! and and the oil delivered to the midpoint t2 of the trough rises to the same elevation on the two ramps in the "1ow setting of the burner, the oil usually reaching an elevation near the bottoms 153 and til of the flame pockets. The flames in the pockets 3i and 32 originate just above the oil level and there is, therefore, little or no danger of the flames being extinguished due to the fact that the flames are anchored close to the wall 25 and the flame pockets, as previously described, are furthermore protected by the baffles 29 and Sil against the direct force of the air current. The small iiames reaching out from the flame pockets on low over the bare surfaces l5 and 5 keep these surfaces hotter than they would be if covered more or less by a thin layer of oil, such as would be present there if the oil retaining wall 31 were not provided. Sudden turn-up is, therefore, not nearly so apt to result in the flames being extinguished, because the first oil rising on the ramps and i5 is promptly vaporized by contact with these hot surfaces, thus building up the flame easily from low to high In the starting of the burner the surfaces it and 46 are preheated, and we have found that with the present construction tlie burner can be started successfully very soon after the preheating torch is inserted. in passing, it will be noticed that the tray 9 has a series of Steps 15S-52 formed onv the spiral bottorn 33, similar to the steps of a spiral staircase. The rst two steps it and til are parallel with the trough 35. This formation is to prevent surging of oil when the burner is suddenly turned from low to high Under those conditions the tray 9 is not heated to a high enough temperature, because of the low flame, and, therefore, does not have sumcient residual heat to vaporize the suddenly increased inflow of oil. If it were not for the steps lll-2, a deep pool of oil would form in the groove 23 and flood a large portion of the spiral bottom 33, and the air current impinging upon the edge of this pool would wash some oil up onto the hotter part of the tray and cause vapor-ization there, with the result that the burner would operate with an uneven flame until the tray would reach a higher temperature, due to the radiant heat oi the larger flame, after which the level of the oil would gradually subside to the edge of the groove 23 or reach some other point of stability, With the present construction, when. the burner is turned up for a higher llame, the oil rises first along the ramps 40 and Il! and then along the ramps l5 and 45, thus confining the oil as much as possible closer to the air intake so as to produce an intimate mixture of air and vapor. When the oil enters faster than it is vaporized, as, for example, upon sudden turn-up from low to high, oil fills the groove 23 and finally runs out over the lower portion of the spiral bottom 33 `to the step 48. There the oil is again confined as close as possible to the air intake to continue producing an intimate mixture of air and vapors to avoid the condition previously mentioned. Ordinarily the flame builds up fast enough so that the oil does not rise past the step L18, but if it should, it is confined by the step 48, and so on, with steps 5i), and 5l, and 52. At each step there is a sharply delined boundary for the pool so that the oil cannot surge :forward and cause an uneven flame. When the tray is heated up properly by the larger flame, the level of oil usually subsides until the oil is vaporized mostly in the groove 23.

In accordance with another feature of our invention, an air duct 53 is provided cast integral with the end of the air conduit 6 and bottom of the overflow pan ill to divert a certain amount of air from the air conduit, as indicated by the arrows e in Fig. 3, and discharge this air into the combustion head 'E under the burner tray 5 at a point far enough away from the groove 23 to eliminate any likelihood of this incoming air cooling the burner tray to such an extent that it will interfere with good vaporization of the oil. rlhe air inlet opening 54 from the duct 53, as clearly indicated, in Fig. 2, is just beneath the step 52, which is the one most remote from the groove E3. A substantially semi-circular baille plate 55, welded or otherwise suitably secured on top of the neck 56 which defines the air inlet opening 54', serves the double purpose of cutting down the air flow through the opening 5d to the extent desired and also directing the air away from that portion of the tray in which the groove 23 is provided, the baffle 55 being on that side of the neck 56 toward the groove so that the incoming air, taking the shortest path from the neck 55, will flow up around the edges of the tray 9, as indicated by the arrows ,f in Fig. 2, on the far side of the tray remote from the air conduit 6, the air being delivered into the ame as secondary air to support combustion and avoid carbon deposits. This air prevents overheating of the tray 9 and also keeps the overiiow pan I9 cool, so that there is no danger of either of these parts cracking. y

It is believed the foregoing description conveys a good understanding of the objects and advantages of our invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

We claim:

l. A burner tray for an oil burning combustion head, comprising a body having one portion thereof formed to provide a generally rectangular depression into which oil to be burned is adapted to be delivered in a stream from an oil delivery pipe disposed thereover, said body having walls enclosing the opposite ends of said depression to denne flame pockets therein, and said body having a wall extending longitudinally in said depression between the bottoms of the flame pockets so as to dene two troughs in the depression on opposite sides of said wall, the bottom of one trough into which the oil stream is delivered being defined by outwardly and upwardly inclined ramps extending from a midpoint in the trough below the elevation of the bottoms of the flame pockets outwardly and upwardly to the level of said bottoms, and the bottom of the other trough being defined by ramps extending inwardly and upwardly toward a midpoint in the trough from the elevation of the bottoms of the ame pockets.

2. A burner tray as set forth in claim l, including a vertically extending projection on said body in one side of the first named trough at the middle thereof, having an oil conducting groove provided in the inner side thereof extending substantially vertically from the upper end of said projection to the lower ends of the rst named ramps.

3. A burner tray for a generally circular oil burning combustion head, comprising a generally circular body having approximately one-quarter thereof of generally rectangular form and formed to provide a generally rectangular depression therein, into which oil to be burned is adapted to be delivered in a stream from an oil delivery pipe disposed thereover, the circular portion having a spiral top surface formation extending substantially spirally from a relatively low starting level adjacent one side of the rectangular depression and at one elevation labove the bottom of said depression to a higher take-off level, said body having walls enclosing the opposite ends of said depression to define `ame pockets therein, and said body having' a wall extending longitudinally in said depression between the bottoms of the flame pockets so as to define two troughs in the depression on opposite sides ofv said wall, the bottom of one trough remote from the starting level of said spiral top surface formation being defined by outwardly and upwardly inclined ramps extending from a midpoint in the trough below the elevation of the bottoms of the flame pockets outwardly and upwardly to the level of said bottoms, and the bottom of the other trough next to the starting level of said spiral top surface formation being defined by ramps extending inwardly and upwardly toward a midpoint in the trough from the elevation of the bottoms of the flame pockets.

4. A burner tray as set forth in claim 3, including a vertically extending projection on said body in one side of the first named trough at the middle thereof, having an oil conducting groove provided in the inner side thereof extending substantially vertically from the upper end of said projection to the lower ends of the first named ramps.

5. In a liquid fuel burner, the combination of a bottom member, a burner tray on which liquid fuel is continuously vaporized in the presence of air and burned, said tray being supported over and in spaced relation to said bottom member, an enclosing hood supported on the bottom member in spaced relation annularly with respect to said tray and having a llame outlet opening in the top thereof above said tray, means for continuously delivering liquid fuel onto the top of said tray at one side thereof to be vaporized by contact with the hot surface of the tray, means for continuously supplying air under pressure into said hood over said tray at the point of oil delivery to mix with the vaporized oil to form a readily burnable mixture and to support combustion of such mixture over the tray, and means for continuously supplying air under pressure through an air inlet opening provided in the bottom member at a point in remote relation to the aforesaid oil and air delivery point but beneath the tray for circulation of air between the bottom member and tray and upwardly around the tray into the flame over the tray to further support combustion, while serving by such circulation to prevent overheating of that portion of the tray over and near the air inlet opening.

6. A liquid fuel burner as set forth in claim 5, including a baffle plate partially covering the air inlet opening on that side toward the point of oil and air delivery on said tray to restrict the flow of air to a predetermined extent and direct the air ow away from the point of oil and air delivery to the tray.

7. In a liquid fuel burner, a substantially horizontal casing having bottom and side walls and a top provided with a flame outlet opening, a substantially horizontal air conduit communicating with said casing through the side Wall thereof, a burner tray on the bottom of said casing having therein a liquid fuel vaporization trough below and in juxtaposition to the discharge end of the air conduit and a raw liquid fuel trough in transverse relation to said air conduit and between the discharge end thereof and said fuel vaporization trough, a substantially vertical partition wall on said tray disposed in transverse relation to the discharge end of the air conduit and extending lengthwise of and between but terminating short of both ends of said troughs leaving the ends thereof in communication with one another, the bottom of the raw liquid fuel trough being generally V-shaped to provide outwardly and upwardly inclined ramps at an acute angle to the substantially horizontal plane of said casing reaching to the opposite ends of the partition wall, the bottom of the fuel vaporization trough being of inverted V-shape to provide ramps extending from the opposite ends of the partition wall inwardly and upwardly at an acute angle to the substantially horizontal plane of said casing toward one another, a fuel supply pipe communicating with said raw liquid fuel trough to deliver raw liquid fuel thereto, and means to define flame pockets enclosing the ends of the troughs alongside and out of the path of the air entering said casing.

8. In a liquid fuel burner, a substantially horizontal casing having bottom and side walls and a top provided with a flame outlet opening, a substantially horizontal air conduit communicating with said casing through the side wall thereof, a burner tray in said casing resting on the bottom thereof having a fuel vaporization trough provided therein extending transversely relative to the discharge end of said air conduit and also having a raw liquid fuel trough provided therein in parallel relation to the fuel vaporization trough behind a front wall extending transverselyrelative to the discharge end of said air conduit, said wall rising to a predetermined elevation above a spiral surface on the tray extending from the fuel vaporization trough, whereby air flowing substantially horizontally over said wall and over said fuel vaporization trough will entrain vapors rising therefrom and carry the burning mixture over said spiral surface, Said burner tray having a substantially vertical partition wall parallel lto the front wall extending lengthwise of and between said fuel vaporization trough and the raw liquid fuel trough but terminating short of the ends of said troughs leaving the ends of said troughs in communication with one another, the bottom of the raw liquid fuel trough being generally V-shaped to provide outwardly and upwardly inclined ramps at an acute angle to the substantially horizontal plane of said casing reaching to the opposite ends of the partition wall, the bottom l of the fuel vaporization trough being of inverted V-shape to provide ramps extending from the opposite ends of the partition wall inwardly and upwardly at an acute angle to the substantially horizontal plane of said casing toward one another, and a fuel supply pipe communicating with said raw liquid fuel trough to deliver raw liquid fuel thereto.

9. In a liquid fuel burner, a substantially horizontal casing having bottom and side walls and a top provided with a flame outlet opening, a substantially horizontal air conduit communicating with said casing through the side wall thereof, a burner tray in said casing resting on the bottom thereof having a fuel vaporization trough provided therein extending transversely relative to the discharge end of said air conduit and also having a raw liquid fuel trough provided therein in parallel relation to the fuel vaporization trough behind a front wall extending transversely relative to the discharge end of said air conduit, said wall rising to a predetermined elevation above a spiral surface on the tray extending from the fuel vaporization trough, whereby air flowing substantially horizontally over said wall and over said fuel vaporization trough will entrain vapors rising therefrom and carry the burning mixture over said spiral surface, said burner tray having a substantially vertical partition wall parallel to the front wall extending lengthwise of and between said fuel vaporization trough and the raw liquid fuel trough but terminating short of the ends of said troughs leaving the ends of said troughs in communication with one another, Vthe bottom of the raw liquid fuel trough being generally V-shaped to provide outwardly and upwardly inclined ramps at an acute angle to the substantially horizontal plane of said casing reaching to the opposits ends of the partition wall, the bottom of the fuel vaporization trough being of inverted V-shape to provide ramps extending from the opposite ends of the partition wall inwardly and upwardly at an acute angle to the substantially horizontal plane of said easing towardone another, a fuel supply pipe communicating with said raw liquid fuel trough to deliver raw liquid fuel thereto, and a pair of baffles rising from the top of said front wall in laterally spaced relation on opposite sides of the discharge end of the air conduit and shielding the opposite ends of the troughs from the incoming air.

l0. In a liquid fuel burner, a substantially horizontal casing having bottom and side walls and a top provided with a flame outlet opening, a substantially horizontal air conduit communicating with said casing through the side wall thereof, a burner tray in said casing resting on the bottom thereof having a fuel vaporization trough provided therein extending transversely relative to the discharge end of said air conduit and also having a raw liquid fuel trough provided therein in parallel relation to the fuel vaporization trough behind a front wall extending transversely relative to the discharge end of said air conduit, said wall rising to a predetermined elevation above a spiral surface on the tray extending from the fuel vaporization trough, whereby air iiowing substantially horizontally over said wall and over said fuel vaporization trough will entrain vapors rising therefrom and carry the burning mixture over said spiral surface, said burner tray having a substantially vertical partition wall parallel to the front wall extending lengthwise of and between said fuel vaporization trough and the raw liquid fuel trough but terminating short of the ends of said troughs leaving the ends of said troughs in communication with one another, the bottom of the raw liquid fuel trough being generally V-shaped to provide outwardly and upwardly inclined ramps at an acute angle to the substantially horizontal plane of said casing reaching to the opposite ends of the partition wall, the bottom of the fuel vaporization trough being of inverted V-shape to provide ramps extending from the opposite ends of the partition wall inwardly and upwardly at an acute angle to the substantially horizontal plane of said casing toward one another, a fuel supply pipe communicating with said raw liquid fuel trough to deliver raw liquid fuel thereto, a pair of baffles rising from the top of said front wall in laterally spaced relation on opposite sides of the discharge end of the air conduit and shielding the opposite ends of the troughs from the incoming air, and an air deector over said tray extending transversely relative to the discharge end of the air conduit and arranged to direct air downwardly into the fuel vaporization trough.

1l. A burner tray for an oil burning combustion head, comprising a body having one portion thereof formed to provide a generally rectangular depression into which oil to be burned is adapted to be delivered in a stream from an oil delivery pipe disposed thereover, said body having walls enclosing one end of said depression to define a fiarne pocket therein, and said body having a wall extending longitudinally in said depression away from the bottom of the flame pocket so as to dene two troughs in the depression on opposite sides of said wall, the bottom of one trough into which the oil stream is delivered being defined by an outwardly and upwardly inclined ramp extending from a low level in the trough below the elevation of the bottom of the flame pocket outwardly and upwardly to the level of said bottom, and the bottom of the other trough being defined by another ramp extending inwardly and upwardly toward a high level in the trough from the elevation of the bottom of the flame pocket.

12. A burner tray as set forth in claim 11, including a vertically extending projection on said body in one side of the rst named trough in spaced relation to the bottom of the flame pocket, having an oil conducting groove provided in the inner side thereof extending substantially vertically from the upper end of said projection to the lower end of the rst named ramp.

JOHN H. MCILVAINE. PETER I. HOLLMAN. 

